Accommodative intraocular lens

ABSTRACT

A two-optic accommodative lens system. The first lens has a negative power and is located posteriorly against the posterior capsule. The periphery of the first optic contains a pair of clasps. The second optic is located anteriorly to the first optic and is of a positive power. The peripheral edge of the second optic contains a pair of locking arms that fit into the clasps contained on the periphery of the first optic to lock the second optic onto the first optic, but allow for rotation of the arms within the clasps. Hinge structures on the locking arms allow the second optic to move relative to the first optic along the optical axis of the lens system in reaction to movement of the ciliary muscle.

This application is a divisional of U.S. patent application Ser. No.10/134,877, filed Apr. 29, 2002 now U.S. Pat. No. 6,695,881.

BACKGROUND OF THE INVENTION

This invention relates generally to the field of intraocular lenses(IOL) and, more particularly, to accommodative IOLs.

The human eye in its simplest terms functions to provide vision bytransmitting light through a clear outer portion called the cornea, andfocusing the image by way of a crystalline lens onto a retina. Thequality of the focused image depends on many factors including the sizeand shape of the eye, and the transparency of the cornea and the lens.

When age or disease causes the lens to become less transparent, visiondeteriorates because of the diminished light which can be transmitted tothe retina. This deficiency in the lens of the eye is medically known asa cataract. An accepted treatment for this condition is surgical removalof the lens and replacement of the lens function by an artificialintraocular lens (IOL).

In the United States, the majority of cataractous lenses are removed bya surgical technique called phacoemulsification. During this procedure,an opening is made in the anterior capsule and a thinphacoemulsification cutting tip is inserted into the diseased lens andvibrated ultrasonically. The vibrating cutting tip liquifies oremulsifies the lens so that the lens may be aspirated out of the eye.The diseased lens, once removed, is replaced by an artificial lens.

In the natural lens, bifocality of distance and near vision is providedby a mechanism known as accommodation. The natural lens, early in life,is soft and contained within the capsular bag. The bag is suspended fromthe ciliary muscle by the zonules. Relaxation of the ciliary muscletightens the zonules, and stretches the capsular bag. As a result, thenatural lens tends to flatten. Tightening of the ciliary muscle relaxesthe tension on the zonules, allowing the capsular bag and the naturallens to assume a more rounded shape. In the way, the natural lens can befocus alternatively on near and far objects.

As the lens ages, it becomes harder and is less able to change shape inreaction to the tightening of the ciliary muscle. This makes it harderfor the lens to focus on near objects, a medical condition known aspresbyopia. Presbyopia affects nearly all adults over the age of 45 or50.

Prior to the present invention, when a cataract or other diseaserequired the removal of the natural lens and replacement with anartificial IOL, the IOL was a monofocal lens, requiring that the patientuse a pair of spectacles or contact lenses for near vision. Allergan hasbeen selling an bifocal IOL, the Array lens, for several years, but dueto quality of issues, this lens has not been widely accepted.

Several designs for accommodative IOLs are being studied. For example,several designs manufactured by C&C Vision are currently undergoingclinical trials. See U.S. Pat. Nos. 6,197,059, 5,674,282, 5,496,366 and5,476,514 (Cumming), the entire contents of which being incorporatedherein by reference. The lens described in these patents is a singleoptic lens having flexible haptics that allows the optic to move forwardand backward in reaction to movement of the ciliary muscle. A similardesigns are described in U.S. Pat. No. 6,302,911 B1 (Hanna), U.S. Pat.Nos. 6,261,321 B1 and 6,241,777 B1 (both to Kellan), the entire contentsof which being incorporated herein by reference. The amount of movementof the optic in these single-lens systems, however, may be insufficientto allow for a useful range of accommodation. In addition, as describedin U.S. Pat. Nos. 6,197,059, 5,674,282, 5,496,366 and 5,476,514, the eyemust be paralyzed for one to two weeks in order for capsular fibrosis toentrap the lens that thereby provide for a rigid association between thelens and the capsular bag. In addition, the commercial models of theselenses are made from a hydrogel or silicone material. Such materials arenot inherently resistive to the formation of posterior capsuleopacification (“PCO”). The only treatment for PCO is a capsulotomy usinga Nd:YAG laser that vaporizes a portion of the posterior capsule. Suchdestruction of the posterior capsule may destroy the mechanism ofaccommodation of these lenses.

There have been some attempts to make a two-optic accommodative lenssystem. For example, U.S. Pat. No. 5,275,623 (Sarfarazi), WIPOPublication No. 00/66037 (Glick, et al.) and WO 01/34067 A1 (Bandhauer,et al), the entire contents of which being incorporated herein byreference, all disclose a two-optic lens system with one optic having apositive power and the other optic having a negative power. The opticsare connected by a hinge mechanism that reacts to movement of theciliary muscle to move the optics closer together or further apart,thereby providing accommodation. In order to provide this “zoom lens”effect, movement of the ciliary muscle must be adequately transmitted tothe lens system through the capsular bag, and none of these referencesdisclose a mechanism for ensuring that there is a tight connectionbetween the capsular bag and the lens system. In addition, none of theselenses designs have addressed the problem with PCO noted above.

Therefore, a need continues to exist for a safe and stable accommodativeintraocular lens system that provides accommodation over a broad anduseful range.

BRIEF SUMMARY OF THE INVENTION

The present invention improves upon the prior art by providing atwo-optic accommodative lens system. The first lens has a negative powerand is located posteriorly against the posterior capsule. The peripheryof the first optic contains a pair of clasps. The second optic islocated anteriorly to the first optic and is of a positive power. Theperipheral edge of the second optic contains a pair of locking arms thatfit into the clasps contained on the periphery of the first optic tolock the second optic onto the first optic, but allow for rotation ofthe arms within the clasps. Hinge structures on the locking arms allowthe second optic to move relative to the first optic along the opticalaxis of the lens system in reaction to movement of the ciliary muscle.

Accordingly, one objective of the present invention is to provide a safeand biocompatible intraocular lens.

Another objective of the present invention is to provide a safe andbiocompatible intraocular lens that is easily implanted in the posteriorchamber.

Still another objective of the present invention is to provide a safeand biocompatible intraocular lens that is stable in the posteriorchamber.

Still another objective of the present invention is to provide a safeand biocompatible accommodative lens system.

These and other advantages and objectives of the present invention willbecome apparent from the detailed description and claims that follow.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 is an enlarged top plan view of the first optic of a firstembodiment of the lens system of the present invention.

FIG. 2 is an enlarged cross-sectional view of the first optic of a firstembodiment of the lens system of the present invention taken at line 2—2in FIG. 1.

FIG. 3 is an enlarged top plan view of the second optic of a firstembodiment of the lens system of the present invention.

FIG. 4 is an enlarged cross-sectional view of the second optic of afirst embodiment of the lens system of the present invention taken atline 4—4 in FIG. 3.

FIG. 5 is an enlarged partial cross-sectional view taken at circle 5 inFIG. 4.

FIG. 6 is an enlarged top plan view of the first optic of a secondembodiment of the lens system of the present invention.

FIG. 7 is an enlarged cross-sectional view of the first optic of asecond embodiment of the lens system of the present invention taken atline 7—7 in FIG. 6.

FIG. 8 is an enlarged top plan view of the second optic of a secondembodiment of the lens system of the present invention.

FIG. 9 is an enlarged cross-sectional view of the second optic of asecond embodiment of the lens system of the present invention taken atline 9—9 in FIG. 8.

FIG. 10 is a cross-sectional view of the first embodiment of the lenssystem of the present invention illustrated in FIGS. 1-5.

FIG. 11 is a cross-sectional view of the second embodiment of the lenssystem of the present invention illustrated in FIGS. 6-9.

FIG. 12 is a cross-sectional view of the first embodiment of the lenssystem of the present invention illustrated in FIGS. 1-5 andillustrating the lens system implanted within a capsular bag.

FIG. 13 is a cross-sectional view of the second embodiment of the lenssystem of the present invention illustrated in FIGS. 6-9 andillustrating the lens system implanted within a capsular bag.

FIG. 14 is an enlarged top plan view of the first optic of a thirdembodiment of the lens system of the present invention.

FIG. 15 is an enlarged cross-sectional view of the first optic of athird embodiment of the lens system of the present invention taken atline 15—15 in FIG. 14.

FIG. 16 is an enlarged partial cross-sectional view taken at circle 16in FIG. 15.

FIG. 17 is an enlarged top plan view of the second optic of a thirdembodiment of the lens system of the present invention.

FIG. 18 is an enlarged cross-sectional view of the second optic of athird embodiment of the lens system of the present invention taken atline 18—18 in FIG. 17.

FIG. 19 is an enlarged partial cross-sectional view taken at circle 19in FIG. 18.

FIG. 20 is an enlarged top plan view of the third embodiment of the lenssystem of the present invention illustrated in FIGS. 14-19.

FIG. 21 is a cross-sectional view of the third embodiment of the lenssystem of the present invention taken at line 21—21 in FIG. 20.

FIG. 22 is an enlarged top plan view of the first optic of a fourthembodiment of the lens system of the present invention.

FIG. 23 is an enlarged cross-sectional view of the first optic of athird embodiment of the lens system of the present invention taken atline 23—23 in FIG. 22.

FIG. 24 is an enlarged top plan view of the second optic of a fourthembodiment of the lens system of the present invention.

FIG. 25 is an enlarged cross-sectional view of the second optic of athird embodiment of the lens system of the present invention taken atline 25—25 in FIG. 24.

FIG. 26 is an enlarged partial cross-sectional view taken at circle 26in FIG. 25.

FIG. 27 is an enlarged top plan view of the fourth embodiment of thelens system of the present invention illustrated in FIGS. 26—26.

FIG. 28 is a cross-sectional view of the fourth embodiment of the lenssystem of the present invention taken at line 28—28 in FIG. 27.

DETAILED DESCRIPTION OF THE INVENTION

As best seen in FIGS. 1-5 and 10, lens system 10 of the presentinvention generally consists of posterior optic 12 and anterior optic14. Optic 12 is preferably formed in any suitable overall diameter orlength, for example, around 12 millimeters, for implantation in theposterior chamber. Optic 12 preferably is made from a soft, foldablematerial that is inherently resistive to the formation of PCO, such as asoft acrylic. Optic 14 preferable is made from a soft, foldable materialsuch as a hydrogel, silicone or soft acrylic. Optic 12 may be anysuitable power, but preferably has a negative power. Optic 14 may alsobe any suitable power but preferably has a positive power. The relativepowers of optics 12 and 14 should be such that the axial movement ofoptic 14 toward or away from optic 12 should be sufficient to adjust theoverall power of lens system 10 at least one diopter and preferably, atleast three to four diopters, calculation of such powers of optics 12and 14 being within the capabilities of one skilled in the art ofdesigning ophthalmic lenses by, for example, using the followingequations:P=P ₁ +P ₂ −T/n*P ₁ P ₂  (1)δP=δT/n*P ₁ P ₂  (2)

As best seen in FIGS. 1 and 2, optic 12 is generally symmetrical aboutoptical axis 22 and contains a pair of opposing clasps 16 that areshaped to stretch and fill equatorial region 210 of capsular bag 200.Clasps 16 contain sockets 18 generally defined by latch 20. As best seenin FIGS. 3-5, optic 14 contains a pair of haptics 24 that are connectedto optic 14 by hinge regions 26 and contain locking pins 28 distallyfrom hinge regions 26. As seen in FIG. 10, locking pins 28 are sized andshaped to fit within sockets 18 on optic 12, thereby holding optic 14firmly within optic 12 while still permitting rotation of locking pins28 within sockets 18. One skilled in the art will recognize that sockets18 may be located on hinge regions 26 and that locking pins 28 may belocated on optic 12. In order to insert locking pins 28 within sockets18, sockets 18 may be spread apart slightly, thereby preloading haptics24. Once implanted in an eye, as one skilled in the art will recognize,contraction of capsular bag 200 will cause clasps 16 to collapseslightly, thereby causing compression of optic 14. As optic 14 iscompressed, hinge regions 26 allow optic 14 to vault anteriorly awayfrom optic 12, with locking pins 28 pivoting within sockets 18. Oneskilled in the art will recognize that no specific feature needs to beused to form hinge regions 26 as haptics 24 may be formed from amaterial and/or in such a configuration that haptics naturally flex inthe manner of a hinge.

As best seen in FIGS. 6-9 and 11, lens system 110 of the presentinvention generally consisting of posterior optic 112 and anterior optic114. Optic 112 is preferably formed in any suitable overall diameter orlength, for example, around 12 millimeters, for implantation in theposterior chamber. Optic 112 preferably is made from a soft, foldablematerial that is inherently resistive to the formation of PCO, such as asoft acrylic. Optic 114 preferable is made from a soft, foldablematerial such as a hydrogel, silicone or soft acrylic. Optic 112 may beany suitable power, but preferably has a negative power. Optic 114 mayalso be any suitable power but preferably has a positive power. Therelative powers of optics 112 and 114 should be such that the axialmovement of optic 114 toward or away from optic 112 should be sufficientto adjust the overall power of lens system 10 at least one diopter andpreferably, at least three to four diopters, calculation of such powersof optics 112 and 114 being within the capabilities of one skilled inthe art. One skilled in the art will also recognize that the axialmovement of optic 114 relative to optic 112 is greater in thisembodiment as opposed to the embodiment illustrated in FIGS. 1-5 due tothe longer length of haptic 124 versus haptic 24.

As best seen in FIGS. 6, 7 and 13, optic 112 is generally symmetricalabout optical axis 122 and contains a pair of opposing clasps 116 thatare shaped to stretch and fill equatorial region 310 of capsular bag300. Clasps 116 contain sockets 118 generally defined by latch 120. Asbest seen in FIGS. 8 and 9, optic 114 contains circumferential haptic124 that are connected to optic 114 by hinge regions 126 and containlocking pins 128 distally on the periphery of haptics 124. One skilledin the art will recognize that sockets 118 may be located on clasps 116and that locking pins 128 may be located on haptics 124. As seen in FIG.11, locking pins 128 are sized and shaped to fit within sockets 118 onoptic 112, thereby holding optic 114 firmly within optic 112 while stillpermitting rotation of locking pins 128 within sockets 118. Preferably,locking pins 128 are located approximately 90° from hinge regions 126around the circumference of optic 114. In order to insert locking pins128 within sockets 118, sockets 118 may be spread apart slightly,thereby preloading haptics 124. One skilled in the art will recognizethat no specific feature needs to be used to form hinge regions 126 ashaptics 124 may be formed from a material and/or in such a configurationthat haptics naturally flex in the manner of a hinge.

Once implanted in an eye, as one skilled in the art will recognize,contraction of capsular bag 300 will cause clasps 116 to collapseslightly, thereby causing compression of optic 114. As optic 114 iscompressed, hinge regions 126 allow optic 114 to vault anteriorly awayfrom optic 112, with locking pins 128 pivoting within sockets 118.

As best seen in FIGS. 12 and 13, lens system 10 and 110 fills capsularbag 200 and 300, respectively, following removal of the natural lens. Inorder to remove the natural lens, an opening or rhexis is normally madein the anterior side of capsule 200 or 300. The opening contains rim ormargin 212 or 312 During implantation of system 10 or 110, rim or margin212 or 312 is inserted into socket 18 or 118 prior to the introductionof optic 14 or 114, respectively. Once optic 14 or 114 is installed inoptic 12 or 112, locking pins 28 and 128 help to contain rim 212 or 312within sockets 18 or 118, respectively, thereby maintaining a positivemechanical connection between capsular bag 200 and 300 and lens system10 and 110, respectively. Contraction of capsular bag 200 or 300 willtherefore be more directly translated into contraction of optics 12 and112, respectively. In addition, the self-locking design of sockets 18and 118 prevent capsular bag 200 and 300 from slipping out of sockets 18or 118, respectively.

As best seen in FIGS. 15-21, lens system 410 of the present invention ofthe present invention generally consists of posterior optic 412 andanterior optic 414. Optic 412 is preferably formed in any suitableoverall diameter or length, for example, around 12 millimeters, forimplantation in the posterior chamber. Optic 412 preferably is made froma soft, foldable material that is inherently resistive to the formationof PCO, such as a soft acrylic. Optic 414 preferable is made from asoft, foldable material such as a hydrogel, silicone or soft acrylic.Optic 412 may be any suitable power, but preferably has a negativepower. Optic 414 may also be any suitable power but preferably has apositive power. The relative powers of optics 412 and 414 should be suchthat the axial movement of optic 414 toward or away from optic 412should be sufficient to adjust the overall power of lens system 410 atleast one diopter and preferably, at least three to four diopters,calculation of such powers of optics 412 and 414 being within thecapabilities of one skilled in the art as described above.

As best seen in FIGS. 15 and 16, optic 412 is generally symmetricalabout optical axis 422 and contains a circumferential socket 418. Asbest seen in FIGS. 17-19, optic 414 contains a pair of hemisphericalhaptics 424 that are connected to optic 414 by hinge regions 426 andcontain circumferential locking rib 428. As seen in FIG. 21, locking rib428 is sized and shaped to fit within socket 418 on optic 412, therebyholding optic 414 firmly within optic 412 while allowing rotation oflocking rib 428 within socket 418. Once implanted in an eye, as oneskilled in the art will recognize, contraction of the capsular bag willcause compression of optic 414. As optic 414 is compressed, hingeregions 426 allow optic 414 to vault anteriorly away from optic 412,with locking rib 428 pivoting within socket 418.

As best seen in FIGS. 22-28, lens system 510 of the present invention ofthe present invention is similar to system 510 and generally consists ofposterior optic 512 and anterior optic 514. Optic 512 is preferablyformed in any suitable overall diameter or length, for example, around12 millimeters, for implantation in the posterior chamber. Optic 512preferably is made from a soft, foldable material that is inherentlyresistive to the formation of PCO, such as a soft acrylic. Optic 514preferable is made from a soft, foldable material such as a hydrogel,silicone or soft acrylic. Optic 512 may be any suitable power, butpreferably has a negative power. Optic 514 may also be any suitablepower but preferably has a positive power. The relative powers of optics512 and 514 should be such that the axial movement of optic 514 towardor away from optic 512 should be sufficient to adjust the overall powerof lens system 510 at least one diopter and preferably, at least threeto four diopters, calculation of such powers of optics 512 and 514 beingwithin the capabilities of one skilled in the art as described above.

As best seen in FIGS. 22 and 23, optic 512 is generally symmetricalabout optical axis 522 and contains a circumferential rib 528, which issimilar to rib 428 in system 410. As best seen in FIGS. 24-26, optic 514contains a pair of hemispherical haptics 524 that are connected to optic514 by hinge regions 526 and contain circumferential socket 518. As seenin FIG. 28, locking rib 528 is sized and shaped to fit within socket 518on optic 514, thereby holding optic 514 firmly within optic 512 whileallowing rotation of locking rib 528 within socket 518. Once implantedin an eye, as one skilled in the art will recognize, contraction of thecapsular bag will cause compression of optic 514. As optic 514 iscompressed, hinge regions 526 allow optic 514 to vault anteriorly awayfrom optic 512, with locking rib 528 pivoting within socket 518.

This description is given for purposes of illustration and explanation.It will be apparent to those skilled in the relevant art that changesand modifications may be made to the invention described above withoutdeparting from its scope or spirit.

1. A method of retaining a lens in a capsular bag, comprising the stepsof: a) providing a first optic having a clasp with a socket; b)providing a second optic having at least one haptic, the haptic beingconnected to the second optic by a hinge region, the hinge regionallowing the second optic to vault away from the first optic in reactionto of the first optic, the haptic further containing a locking pin, thelocking pin sized and shaped to be received in the socket; c) providingan opening in an anterior capsular bag, the opening having a rim; d)placing the rim of the anterior capsule opening in the socket; and e)inserting the locking pin into the socket so as to retain the rim in thesocket and movably attach the second optic to the first optic.
 2. Thelens of claim 1 wherein the first optic and the second optic comprise asoft acrylic.
 3. The lens of claim 1 wherein the second optic comprisesa hydrogel.
 4. The lens of claim 1 wherein the second optic comprisessilicone.
 5. The lens of claim 1 wherein the locking pin and socket aresized and shaped to retain an anterior capsular rhexis rim when thelocking pin is install within the socket.